Preset for antenna wire



Sept. 12, 1950 v McKEE ETAL 2,521,737

PRESET FOR ANTENNA WIRE Filed July 8, 1944 6 Sheets-Sheet 2 9 2 DRUM COUNTER '9 T ELQEL" 43 /OUT L- IN A g i CHANNEL SELECTOR SWITCH D C B A F I G. 2

INVENTOR. ROBERT E.KESTER HENRY R.SMITH Sept. 12, 1950 D. l. MOKEE 'ETAL PRESET FOR ANTENNA WIRE 6 Sheets-Sheet 3 Filed July 8, 1944 Aura/M1161 INVENTOR ROBERT E KESTER Sept. 1950 D. l. MCKEE ETAL 2,521,737

PRESET FOR ANTENNA WIRE Filed July 8, 1944 6 Sheet-s-Sheet 5 'IIIIIIIIIA //V VE N 70/? ROBERT E. KES TER HENRY R SM/TH DWIGHT MGKEE P 1950 D. l. MCKEE ETAL 2,521,737

PRESET FOR ANTENNA WIRE Filed July 8, 1944 6 Sheets-Sheet 6 //v l/EN 70/? ROBERT E. KESTER HENRY R. SMITH DWIGHT lgk 5 WW I A r TORNE r Patented Sept. 12, 1950 PRESET FOR ANTENNA WIRE Dwight I. McKee, Robert E. Kester, and Henry R. Smith, Dayton, Ohio Application J uly 8, 1944, Serial N0. 544,126

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 3'70 0. G. 757) 2 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates. to airborne radio antenna equipment and more particularly to a preset radio. antenna paying-out and reeling-in mechanism and system.

Airborne radio antennas at the present time are customarily released by use of a hand-operated switch on a reelcontrol box bearing the indications out, in, and off. The reel control box may be equipped with an indicating device informing the operator of the length of antenna wire that is reeled out. For optimum reception, the length of the released antenna wire should bear an accurate relation to the wavelength of the electrical impulses that are transmitted and received.

The older forms of antenna-length indicating devices have operated in units of revolutions of the antenna spool. Where many layers of antenna wire are superimposed upon an antenna spool, the first layer is of considerably less length than the last layer of wire upon the spool. errors in this older method of computation of the length of released antenna wire, where the computation is on the basis of number of revolutions of the antenna spool, vary directly with the number of spool revolutions.

The objects of the present invention include the provision of a device for accurately controlling the length of the antenna Wire that is unreeled from a plane in flight, so that this length may bear a definite optimum relation to the wavelength of the radio message-bearing electrical impulses that it is to transmit or receive; an improved device for reeling out and taking in an.- tennas from airborne equipment, automatically or by manual control, as preferred; and an im proved antenna release that is adapted to be preadjusted so that a plurality of predetermined lengths of antenna wire, capable of optimum. signal transmission or reception, can be depended upon.

With the above and other objects in view which will be apparent to those who are informed about and are familiar with the problems and limitations in the field of airborne antennas and the like, suitable illustrative embodiments of the present invention in the forms of circuit diagrams illustrating the electrical connections for an assembly are shown in the accompanying drawings wherein:

Fig. l is a simplified circuit diagram limited The 11 dash-line 8.

to one channel member and Vernier assembly of one form of the present invention;

Fig. 2 is a detailed circuit diagram of a multiple channel and Vernier assembly common to the several illustrated forms of the invention Fig. 3 is a circuit diagram of a further form of a motor, relay and switch part of a circuit that supplements the part of the circuit that is 7 shown in Fig. '2; v

Fig. 4 is a circuit diagram of another form of motor, relay and switch part of the circuit that supplements the part of the circuit shown in Fig. 2;

Fig. 5 is an enlarged fragmentary plan view of the Vernier portionof a mechanism that is shown in Fig. 6;

Fig. 5A is an exploded View of the disk shown in Fig. 5; v t

Fig. 6 is a perspective View of an illustrative antenna preset mechanism part of the present invention; Fig. '7 is an enlarged fragmentary representative elevation of the mid-portion of the mechanism that is shownin Fig. 6. I Referring to the drawings, a motor-driven antenna reel i (Fig. 3) has an antenna wire 2 wound thereon with one or more loops of equal length passing over a wire driven, length-indicating drum 3 (Fig. 2) and from the dru-m'fi through a fairlead (not shown) to a stop (not shown) that engages an antenna Weight t that is attached to the free end of the antenna wire 2, which serves to hold the antenna wire 2 taut when suspended in the slipstream from a plane. A motor rotor 5 is part of a motor that has split field coils, as an out field coil 5, and an in field coil 3, so that the rotor 5 operates in reverse direction for reeling the antenna out orv in with change in the energization of its field soils] The rotation of the motor rotor 5 both feeds out and reels in the antenna wire 2. a v

The energization of the motor outfield coil 6 pays out the antenna wire 2.over the wire-measuring drum 3 that is gripped without slippage by theloop of antenna wire 2 that passes therearound due to the combined gravity and wind drag upon the antenna weight 4. The rotation of the drum 3, that preferably is a definite length, such as 12 inches, for example, in circumference, causes the rotation of an externally-threaded shaft 8', part of a channel-determining mechanism. The continuation of the shaft 8 and the assembly under its control are indicated byna The shaft 8 has its ends journalied in insulat ing end plates ID that are mounted upon a supporting base II, which end plates and base also support a plurality of insulating rods I2. Each insulating rod carries a collar [3, the adjustable position of which longitudinally of the insulating rods may be firmly established in any desired manner, as by the use of set screws or the like that thread radially of the collar I3 to engage the rods I 2. Th positions of the collars I3 on the rods I2 and adjustment of verniers to be described later determine the exposed lengths of antenna wire 2. ferent lengths of antenna wire 2 are provided for. A plurality of conducting rods I5 also extend between the end plates and parallel to the insulating rods I2 with their ends firmly mounted in the end plates II].

One of a pair of flanged contacts I6 is disposed upon each side of each collar I3. The flanged contacts I6 are adapted to slide freely away from the collars I3 longitudinally of the insulating rods upon which they are mounted, against the yielding force of a pair of opposed spirally-wound conducting springs I! that are also mounted in pairs upon each of the insulating rods.

An internally-threaded nut I8 makes threaded engagement with the shaft 8 and carries a contact plate I9 with it. The contact plate I9 is apertured to permit the free passage of the collars I3 therethrough but to engage the flanges on the contacts I6. Electrical conducting material 28 is disposed upon both sides of the contact plate I9. When the antenna wire 2 is completely reeled in, all four contacts 28 on plate I9 are in contact with the out contacts I8 and out springs I I.

When the antenna wire is being payed out over the measuring drum 3, the threaded shaft 8 is rotating and the contact plate I9 travels longitudinally of the channel mounting until an insulating collar I3 is encountered by one of the flanged contacts I6, causing that flanged contact to break connection with the contact plate I9. If plate I9 continues its motion the other flanged contact on the same insulating rod I2 will be engaged by the contact plate l9.

Each contact 28 carried by the contact plate I9 serves one pair of flanged contacts I6 upon one insulating rod, and continues in a pair of brushes that make wiping engagement against an adjacent one of the conducting rods I5.

A plurality of vernier contact discs are rotatably adl'ustably mounted upon an unthreaded end of the shaft 8 and rotate therewith. The vernier discs individually comprise an insulating plastic circular fiat core with two pieces of electrically-conducting plated or copper or brass sheet metal side plates 2| and 22, that are out of contact with each other, riveted upon the flat faces of the flat core 20, shown in Fig. 5. Segments continuing from the outer edges of the side plates 2| and 22 are bent to overlie the peripheral edges of the cores to provide electrically interrupted edge contacts for the vernier discs. The vernier cores make insulating engagement with the shaft 8. A plurality of insulating washers 23 are keyed to the shaft 8 against rotation but free to slide axially thereof. The washers serve to properly space the vernier discs from each other. An insulating cylinder 24 fits loosely upon the end of the shaft 8 and is adapted for being clamped against the outermost vernier disc, with or without an insulating washer 20 interposed therebetween, as preferred, by suitable In the device shown four difoperating of the vernier.

4 means, such as a thumbscrew 25 or the like, to clamp the vernier discs and washers tightly together in preadjusted positions which are retained while the device is in operation.

One set of brushes 33, that are connected to the out circuit, wipe against the vernier side plates 2|. Another set of brushes 3|,that are connected to the in circuit, wipe against the vernier side plates 22. A third set of brushes 32 are mounted to wipe against the peripheral edges of the vernier discs to alternately engage the segments of the side plates 2| and 22 that overlie the peripheries of the vernier cores during the rotation of the vernier discs as the shaft 8 is caused to rotate by the travel of the antenna wire 2. The sets of brushes 3|], 3|, and 32 are mounted to be rigid with respect to the end plates I0 and base Circuit wires are connected individually to the ends of the conducting'rods I5, to the conducting springs I1, and to the ends of the sets of brushes 30, 3|, and 32.,

The simplified circuit that is shown in Fig. l of the, accompanying drawing is limited to a single channel"A andits vernier disc. A particular channel is selected by pressing a button or otherwise engaging a switch upon an antenna control box indicated by dash lines in Fig. l' as comprising channel selecting buttons A, B,'C', and D.

The general scheme of operations comprises presetting the collars I3 on the rods I 2. Each rod I2 may bear calibration marks, to indicate the position at which collar I3 is to be set to preselect the length of antenna wire 2 to be unreeled. The setting of each of the four collars I3 shown determines alength of antenna wire that can be unreeled. The depression of one of the four buttons A, B, C, or D on the control box 35 determines which of the four lengths of antenna wire 2, as determined by the settings of the collars I3 on the rods I2, will then be unreeled. The depression of the control button A applies positive potential through the contact 28 on plate I9, the initially engaged out contact I5, and ,out conducting spring IT, to the relay 40 to close the main out switch 4| and open the switch 36. Closing the switch 4| causes the motor rotor 5 to operate the antenna reel I in th fout direction and feed out the antenna wire 2 over the wire driven drum 3. Vernier controlled out switch 46 is alternately opened and closed through the vernier out contact 2| that alternately contacts brush 32 as shaft 8 rotates and thereby energizes the relay 45, but has no additional eifect. The main in switch 44 is normally open and remains so and vernier controlled in switch 39 is also normally open and remains so. Main in relay 31 is prevented from becoming energized by the open switch 36. When the antenna Wire arrives at its predetermined length, the engagement between the out contact I5 and the contact 28 is broken, deenergizin the relay 40, opening switch 4| and closing switch 35. In this condition contact 28 is not in engagement with either out or in contact I6. Both main out and in switches 4| and 44 are open and both vernier relay circuit switches 36 and 43 are closed. The vernier out" contact 2| maintains contact with brush 32 up to revolution after contact 28 leaves the out contact it. The motor out field winding 6 is energized through switch 46 instead of switch 4| during the v When contact 2| leaves brush 32, switch 46 opens and the reel I may stop or be stopped before vernier contact 22 engages brush 32. Generally the motor will coast past this position through the operation of inertia. Accordingly the antenna will reel out more than is desired, shaft 8 will rotate'so that Vernier in contact 22 will make contact with brmh 32. This will close switch 39 through the operation of relay 3] and the motor .in field winding 7 will be energized and the antenna will be reeled in until brush 3'2 breaks contact with contact 22 Inertia may cause the, antenna to reel out more than specified above so that contact 28 makes contact with the main in contact It and the main in conducting spring I'I. Then the motor in field Winding 'I is energized through switch 33 which is closed by operation of relay i2. Relay i2 opens switch 63 so that any contact between brush 3? and vernier ou contact Z'I will not have any effect. The antenna is reeled in until contact 28 is disengaged from "in contact It, relay E3 is deenergized, switch M is opened and switch 23 is closed. The Vernier in contact 2 2 maintains contact with brush 32 up to revolution after contact 28 leaves fin contact It and the motor in field winding I is energizcd'through switch 39 instead of switch M. The antenna will be reeled in until brush 32 breaks contact with Ver nier in contact 22. The relays and switches under the control of the main contacts and the Vernier contacts operate in a braking manner on the reeling of the antenna and this damped oscillatory winding of the antenna in and out will continue until the system comes to rest with contact 28 between main in and out contacts I5, and similarly with Vernier brush 32 out of contact with both Vernier in and 011' contacts 2| and 22. In thisposition of the contacts both of the switches 39 and 4B are open, both of the main switches ll and 44 are open, both of the motor field coils are deenerg'ized and the predetermined length of the antenna wire 2 for the channel A is exposed.

In a similar manner the predetermined length of the antenna wire 2 under the control of the channel buttons B, C or D may be exposed.

When a new setting of the antennawirc is to he made the corresponding channel button B, C or D is depressed. Since either the in or the ou contact it of the new wire length selector circuit is in engagement with the contact 23, the main switches are closed as in the prior illustration and the selected length of antenna wire 2 is unreeled. One of the buttons A, B, C, or D may be used for completely retracting the an tenna wire 2 or a separate conventional circuit, not shown, between the antenna control box and the-motor field windings 8 and i, may be used for this purpose. The engagement of the out flanged contact I6 with the contact plate I9 energizes the out relay M. The energization of the on relay 49 closes an out? motor switch 4| that energizes the out field it of a motor, causing the motor to reel out the antenna 2. The energization of the out relay M also opens a switch 36 that is ganged with the switch 4 I. The opening of the switch 35 prevents energization of the relay 3'1. Any contact between brush 32 and Vernier in contact 22 with rotation of shaft 8 is prevented from having any effect.

The antenna wire 2 is reeled out from the reel I over the drum 3 which rotates the shaft 8. The

rotation of the threaded shaft a causes the con tact plate I9 to travel longitudinally of the shaft 8, and rotates the vernier discs on the end of the shaft 8. The rotation of the vernier discof the A channel alternately causes the engagement by the brush- 32 ofthe out plate H and the in plate 22. When the out plate 2'I contacts the brush 32, the solenoid 45is energized to close the switch 46. I

The contact plate I9 continuously maintains connection with an out flanged contact" I6 as the contact plate Id and contact I6" travel longitudinally of the insulation rod upon which the out contact IE is slidably mounted, until the insulating collar" I3 that is firmly mounted upon the insulating rod ehgagesthe outiiang'e'd contact I 6 and holds it out of further engagement with the contact plate I9, deenergizingtheout relay 40. When the vernierdisc in plate 2 2 contacts the brush 32 during the rotation of the verniers and prior to the deenergization of the relay '48, no current flows because the switch 36 is open. The deenergization of the relay W permits the motor out switch 4! to open and the Vernier -in" switch 36', that is ganged to the switch 4 I, to close by spring tension.

The contact between the out Vernier plate 2-! and the brush 32 energizes the relay R5 through the spring closed'switch 43 -tob'attery negative, which closes theswitclr ifi. The closing of the switch 46 momentarily continues the energization of the motor out field? S and the continued paying out of the antenna wire '2.

When the clutch and brake mechanism is not used, the in reeling action occurs. A usual clutch and brake mechanism may, ifpreferred, disengage the reel I from motor rotor '5 and brings the reel I to a stop in a, Traction of one revolution before brush 32 is engaged by vernier in plate 22. When the relay 4 2 isenergized by the continued rotation of the threaded shaft 3 until the in contact i6" engages the conductor. on the plate I9. Then in motor switch. 44 is closed and a Vernier out switch 43 that is ganged therewith. is opened. The closure of'the switch 44 energizes the motor infiield l, causing the motor to reel in the antenna wire until' contact 23 on plate It opens connection with in contact I6. When the switch 43 isopen, it prevents relay 45 from being energized whenever, as shaft 8 rotates, there is a connection of brush 3'2wi'th the out plate 2i on the Vernier. The switch 36, now being closed, permits current to flow through the relay 3?, closing the switch 39, when the Vernier in plate 22 engages the brush 32. The motion of the antenna wire 2 is arrested with a predetermined effectual length exposed when the clutch and brake mechanism'is not utilizedand when the Vernier out plate El and the Vernier in plate 22 stop rotating out of contact with the brush 32, which then rests upon an insulated area upon the periphery of the particular Vernier disc involved. The predetermined length of the antenna wire '2 is then exposed from the aircraft for the sending or the receiving of signals and is determined by the positioning of the fixed collars I3 upon the insulation rods 12 and the adjustment of the verniers on the shaft 8. This apparatus has been found experimentally to be accurate to within three inches of the desired lengths, depending upon the accuracy of the aidjustments made and the limitations of the apparatus. The equipment is adapted for one or a plurality of antenna lengths, as illustrated for the group of four antenna lengths that is shown and described herein. I

In the battery of four channels. that is-s'hown in the accompanying drawings, a conductor 50 forms a common connection for the on ends of four out conducting springs I1. A conductor provides common connection for the-in ends of four in conducting springs H. The conductors 52, 53, 54, and 55 individually connect the four conducting rods |5 to four terminals A, B, C, and D of a channel selector switch 56, any one of the terminals of which may be selectively connected by a common conductor 51 to the negative pole of a battery 58 shown in Fig. 3. A conductor 60 provides a common connection fora set of vernier in plate 22 brushes 3| that conform in number to the plurality of channels used, four in this instance. A conductor 6| provides a common connection fora set of vernier out plate 2| brushes 30 that conform in number with the number of channels used. A plurality of conductors 62, 63, 64, and 65 provide individual connections between the conductors 52, 53, 54, and 55 respectively, leading from the individual channel conducting rods I5, and the brushes 32 that individually wipe against the peripheries of the vernier discs carried by the shaft 8.

The motor and relay assembly that is shown in Fig. 3 of the accompanying drawings is supplementary to the channel and vernier assembly that is shown in Fig. 2. The conductor 58 from the out ends of the out springs I1 is joined with the conductor 6| from the brushes contacting the out plates 2| of the vernier between a voltage controlling resistor 68 and an out relay 61 that is adapted for operating a motor out field switch 88. The conductor 5| from the in ends of the in conducting springs I1 is joined with the conductor 60 between a voltage dropping resistor 69 and an in relay 10 that is adapted for operating a motor in field switch 1|. The resistors 66 and 69 serve to prevent the action of one or the other of the relays 61 or 10 when the sense of the vernier action is opposed to the rough adjustment action. Voltage is supplied simultaneously to both relay coils 61 and 10 in this circumstance. To one relay coil the voltage is supplied directly from the battery 58 and to the other relay coil voltage is supplied through one of the resistors. The relay to which voltage is supplied directly will be energized. Conductor 5| is a direct connection to the plurality of in contact springs 1.

When the vernier action opposes the rough adjustment action initially, either the out relay winding 61 or the in relay winding 10 is energized, depending upon which one of the relays receives a sufficient voltage to trip it when the other relay receives an inadequate tripping voltage because of the series resistor 66 or 69. In the absence of resistors 66 and 69 the action in the circuits shown in Fig. 3, would be indeterminate.

As shown on the supplementary circuit diagrams in Figs. 2 and 3 of the drawings, assuming the antenna wire 2 to be in, and the A button depressed, positive potential from the battery 58 may follow two paths through the switches 68 and 1| when these switches are in their normal spring controlled positions shown. Positive potential from the positive terminal of the battery 58 may pass through the switch H to out relay winding 61, through conductor 50, that by-passes resistor 66, to out conducting spring |1, out contact I6, contact 28 on plate I9, conducting rod I5, conductor 52, channel selector switch 56, and returned through conductor 51 to the negative terminal of the battery 58. This provides full battery voltage to the out relay winding 61,

opening the switch 68 to in relay coil 10 and connecting positive terminal of battery 58 to motor field 6, thereby applying full battery potential thereto. The other path is from thepositive terminal of battery 58 through switch 68, in relay winding 10, resistor 65, conductor 60, vernier brush 3|, to vernier in contact 22. The only time this circuit is complete to battery negative terminal is when vernier brush 32 engages vernier in contact 22. The circuit is then completed through conductor 52, channel selector switch 56, conductor 51 to negative battery terminal. As long as the circuit through the first path is closed the current in that path controls the operation of relay 61, but when the first circuit is open the second takes control. Theresistances 66 and 68 are high enough to prevent operation of the relays by the vernier contacts when the vernier circuit is in opposition to the rough adjustment circuti but the resistances 66 and 69 are low enough to permit control of the relays by the vernier when the rough adjustment circuit is open. In general the lower voltage is appleid to the unwanted side of the circuit. The vernier discs are adjusted by loosening the thumbscrew 25, adjusting the vernier discs on the shaft 8, and then securing the vernierdiscs in place by tightening the thumbscrew 25. The vernier discs, as shown in Fig. 2, are not in any predetermined positions.

The positive pole of the battery 58 is connected to the fixed terminal of the motor out field switch 68 and to the fixed terminal of the motor in field switch 1|. The switches 68 and 1| are normally in the closed position shown. The neg ative pole of the battery 58 is connected to the fixed poles of the three position switches 15 and 16 and to the center contact of three-positionswitch 11, which switches are associated with the 011?, automatic and in connections respectively, on a reel control box 12 that is indicated in clotted outline.

When the reel control box indicator is atthe ofi position, the ganged switches 15, 16 and 11 are open or make no connections between the negative pole of the battery 58 and the motor rotor 5 or the in reeling relay 1!) or the connection 51 to the automatic in and out ree control switching system shown in Fig. 2. I

When the reel control box indicator is placed at the in position, the switch 15 connects ,the negatve pole of the battery 58 with the conductors 5| and 68. This connection energizes the relay 1|] to close the switch 1| toward the relay winding 10 and to energize the motor in field coil 1 and reel in the antenna wire. This connection to the conductor -5| applies negative potential to, or grounds the terminal ends of the in springs I1 and to the conductor 68 energizes or grounds the vernier in plates 22. The switch 16, that is ganged with the switch 15, joins the negative pole of the battery with the motor rotor 5. The switch 11, that also is ganged with the switch 15, is open or its connection between the negative pole of the battery 58 and the conductor 51 is broken.

When the reel control box indicator is placed at the automatic position, the switches 15, 16 and 11 are in the positions indicated in Fig. 3 of the drawings. In the automatic position the switch 15 is open, the switch 16 joins the motor rotor 5 with the negative pole of the battery 58. The switch 11 also applies negative potential through the conductor 51 and conductors 52, 53, 54 and 55 to the conducting rods |5 of the channels. In the off" and in connections of the nection to conductor 57, together with th nections of the positive pole of the batteiy semi switch, the constant 51 to the negative terminal of thebatterySB, is interrupted." This conthrough the sw h as. and the e ay is and through the conductor 60 to the in platesflifof the Vernier discs, sets up the automatic circuit through the channelsand Vernier. The positive pole of the battery 58 is also connected through the switch H and the relay ii'ifa-ndthrou gh the conductor Gil to thefou .plates' 2| of .thevernier discs, further establishing'the circuit through the channels and Vernier. The mechanism so ccnnected functions for war ings particular l'ength of exposed antenna wire selected from the chandrawing and is, like the preceding embodiments, 4

supplementary to the ch annel and ,vernier ssembly that is shownin Fig.2. In this diagram the conductor 5] energizes the rnaster -relay iit that operate the anged switches stand- 8 5. The

operates the switch Bl 'Ihe conductor fit chiergizesthe Vernier relay fiii thatoperates the switchiii). The positive pole of the battery 58 is connectedto one terminal of the relays 86 and 83 and tothe fixedterminals of the switches SL 82, 84:, 8 5,81'Lan'd'39', The terminal or" the relay 86 that is not connected to the conductor '5! is connected to a releasable contact of the switch 8 2-. The polarity applied to the relay coils it and 88 may be reversed if desired in the c'ontrol circuit. Releasable connections of theswitches 82 and S'Fare: ccnnectedto the motor cu field 6. Releasable connections of the switch it and of the switch 89 are connected tothe motor .in' field ;i'. The rotor 5 of themotor isconn'ected 4 to the in and automatic poles of switch 92.

In operation, when the reel control box is set at automatic contact between the contact plate I9 and the out flanged contact it continues through the out spring F, and conductor 5% to energize the relay. 89. The energized relay 88 opens the switch 8!, breaking connection with the in plates 22 of the Vernier discs through the relay 88 and conductor 6%, and closes the switch 82 that energizes the motor out field 6.

The motor rotor 5 then functions to feed out the antenna wire 2 from the antenna reel l and over the drum 3.

The antenna wire 2 continues to be fed out until the travel of the contact plate l9 breaks its connection with the out flanged contact it which deenergizes the motor out field 6 and closes the switch 8|. If the velocity of the drum 3 is sufficient to cause the contact plate E9 to engage the in flanged contact 6 for the selected channel determining the desired length of the antenna wire 2, the relay 83 is energized to open the switch 84 and to close the switch 85 which energizes the motor in field I. The connections through the switches 81 and 89 to the 5 motor field coils 3 and 1 and through the switches 81 and 8 3 to the Vernier discs, adjust the an tenna wire 2 to within a reasonable limit of its desired length, depending upon the accuracy of the positions of the collars E3 upon the insulating rods l2, the Vernier adjustments, and the operative limitations of the devices.

In the modification shown in Fig. 4 a plurality of ganged manually-operated switches 90, 9! and 92, have been added. The suggested manual switches comprise adjustments for automatic,

'f fifffand reel i n"setti ngs.j As shown in the Fig. 4 diagram, the fixed' 'ost of the swat-ago is connected with the-conductor so. The fixed posts of the switches 91 andtz are connectedto thenegative post of thebattery 58. The switch 9i? has one movable contact adapted to be connected to the negative terminal of the relay as shown, its other two connections being open. The switchfil has one movable contact adapted to be connected to the conductor 5!, its other two connections being open. T'heswitch' 92' has two movable'cont'actsadapted,to be co'nnectedto the motor rotor 5 and one connection that is open.

Inoperation, the ganged switches 90, Stand 92 are changeable simultaneously from the "automatic" position shown in thecircuit diagram to the indicated" positions.

When in the automatic position, the switch 9t energizes the relay from the out flanged contacts HS when the latter are engage 'd to cause the antenna wire Zft'o be reeled out. In the automatic position the switch 91 is open or not connected and the switchfifi connects'the negative post of the battery 58' with the motor rotor 5. On these positions the length of the antennafwire 2 is adjusted automaticallyin the mannerthat has beenpreviously described.

Whenin the off positionallo'f the switches 90, iii, and 92 are'disconnected. V/fhenin the reel in position, the switchilii i d on ted; hesw t hii e zest erel in to openthe switch 8t, n to" closeith'e switch 815 and to energize the motor fin, e1d l and reel in the antenna wire 2; and the switches connects the motor rotor i to the negative pester the battery 58'.

In comm n with the other motor relay circuits that aif e" disclosed herein, this circuit serves to quickly alld addllfat elyad jllstth length of ali antenna" wir'e toa desired plurality or predetermined lengths.

It will be understood that the devices and circuit diagrams that are disclosed herein and the individual parts thereof have been submitted for the purposes of illustrating and describing the present invention, and that various changes, substitutions, and modifications therein and the particular use cited, may be made without departing from the scope of the invention as defined bythe appended claims.

What we claim is:

l. A radio antenna wire preset system comprising, in combination, an antenna wire, a rotatable antenna reel to which an attached end of said antenna wire is secured and upon which. said antenna wire is wound, a motor having split field coils for reversing the direction of operation of the rotor part thereof and being coupled to said reel for winding or unwinding said antenna wire, an antenna weight secured to an unattached end of said antenna wire, an antenna wire regulating drum of known circumferential dimension interposed between said antenna reel and said antenna weight, a rotatable threaded shaft upon which said drum is non-rotatably mounted, a

carriage plate having at least one electrical contact and being threadably mounted on said shaft to be controlled by the travel of said antenna wire through the operation of said shaft to be moved longitudinally along said shaft, a pair of Vernier contacts adjustably mounted in opposed relationship upon said shaft to be rotated therewith for cooperating with said one contact in adjusting the exposed length of said antenna wire to a prearranged to be selectively controlled in their op- ,inounte'd at spaced points along said shaft in position to'make connection with said one contact in accordance withthe position of said car- H riag e plate along said shaft, a plurality of first to be selectively energized by the engagement of said main contacts, a plurality of first switches eration by said first relay windings and coupled to' said field coils for controlling the paying out and the reeling of said antenna wire in accordance with the connection between said one con- Vi, "tact and one of said main contacts, an additional 15 contact mounted to make connection alternately with said Vernier contacts, a plurality of second relay windings respectively connected between 'one of said Vernier contacts and said additional reeling in of said antenna wire, and conditioning means coupled between said first and second relays and switches to render said second relays and switches efiective to control said motor only when said first relays and switches are ineffective.

2. A radio antenna wire exposed length adjust-' ing mechanism, comprising in combination an v carriage plate having at least one electrical con- 'tactand threadably: mounted on said shaftto be moved. longitudinally therealong with rotation of said shaft and a pair of main contacts mounted at spaced points along said shaft in position to make connections with said one contact, a Vernier mechanism operated'by said shaft for controlling finely the exposed length of antenna wire passing over said drum, said Vernier mechanism including a pair of Vernier contacts rotatably mounted in opposed relationship on said shaft and an additional contactmounted adjacent said shaft in position to be coupled alternately to said Vernier contacts, an antenna carrying reel, a motor coupled to operate said reel and having splitfield coils for reversing the direction of operation of the rotor part thereof, a pair of first coupling means each between one of said split field coils and one of said main contacts for controlling the operation of said motor in accordance with the position of said carriage plate along said shaft, a pair of second coupling means each between one of said verm'er contacts and one of said field coils for finely controlling the operation of said motor, and conditioning means coupled between said first and second coupling means for rendering said second coupling means effective onlywhen said first coupling means is ineffective and said carriage plate is between said main contacts.

' DWIGHT I. McKEE.

ROBERT E. KESTER. HENRY R. SMITH.

REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS 1 Number I Name Date 2,249,836 Lear July 22, 1941 2,351,411 Doughty a June 13, 1944 

